1. Background—Field of the Invention
The invention relates to an electromagnetic inclinometer and a method for measuring inclination using said inclinometer.
2. Background—Prior Art
There are many types of inclinometer available on the market for use in a wide variety of applications such as aircraft, geodetic engineering and general land surveying.
U.S. Pat. No. 4,15,7619 discloses an inclinometer for use in measuring water flow rates comprising a coil energised to produce a magnetic field extending along a normally vertical axis of the device and a flux gate assembly adapted to respond to a horizontal component of that field upon tilting movement of the axis to a inclined non-vertical position. The output will vary in response to change in inclination The flux gate assembly consists of a gimballed arrangement, which is held in an oil filled cavity in which the oil serves to damp the motion of the gimballed arrangement. This arrangement is very robust being adapted to work at oil well formation temperatures but is inevitably quite complex and unsuitable for many applications.
Another application of inclinometers is in marine applications, where they are used as a control device in satellite based navigation systems. Such inclinometers may be fluid based or solid state devices. The fluid devices typically comprise a small bulb having an electrolyte and a plurality of substantially similar electrodes. As the inclinometer is tilted, the fluid will remain level due to the effect of the Earth's gravitational field but the depth to which the electrodes are in contact with the electrolyte changes. This produces a measurable change in the conductance or capacitance between the electrodes, which can be used to calculate the inclination present.
These devices haven proven in the field to be simple and rugged but suffer a number of drawbacks. In particular, they can be slow to recover from shocks as the fluid will be shaken up and give false readings due to the presence of air bubbles and there is tendency for the electrolyte to lose conductivity over time due to electrolysis.